Effect of Lithium on Flagellar Length in Chlamydomonas reinhardtii

Abstract

. We have found that Li+ causes the flagella of Chlamydomonas reinhardtii to elongate. After incubation with 50 mM Li+ for 3–4 hr, flagellar length increased to about 1.4 times the original length. However, the addition of 50 mM Li+ after flagellar amputation caused the regeneration of only half-length flagella, similar to those regenerated in the presence of 20 μg/ml cycloheximide. When regenerated flagella grown in the presence of either Li+ or cycloheximide were re-amputated, they did not regrow. These results suggest that (1) Li+ removes a suppressor(s) in the regulatory mechanism which normally controls flagellar length, (2) flagellar length may exceed a length-dependent “maximum” value (Tamm, S. L., 1967, J. Exp. Zool., 164, 163–186), and (3) Li+ inhibits the protein synthesis required for the complete regeneration of flagella. Thus, normal flagella elongate to 1.4 times their original length in the presence of 50 mM Li+ by using flagellar precursors from a preexisting cytoplasmic pool. © 1987, Japan Society for Cell Biology. All rights reserved.